1. Field of the Invention
This invention relates generally to the detection of analytes, and, more particularly, to a system using a fiber optic probe for sensing the concentration of an analyte in a fluid situated at a remote location.
2. Description of the Related Art
In a fiber optic based laser induced fluorescence sensor probe, light propagates through an optical fiber (hereinafter "fiber") to an active region. In the active region, evanescent or distal field excitation leads to a fluorescent signal from an analyte outside the fiber. The fluorescent signal propagates back through the fiber and is used to estimate the concentration of the analyte. Typical uses for such probes include detecting hazardous waste, monitoring the contamination of a gas or process stream, and measuring engine temperatures.
The propagating energy field in a fiber induces native fluorescence of the fiber on the path toward the probe. It would be desirable to reduce the level of induced fluorescence and thus reduce background noise. Additionally, it would be desirable to have a compact, portable system with multiple probes which can be used to simultaneously measure the concentrations of various predetermined analytes.